Gripping dies for pipe wrenches and similar devices



Dec. 6, 1960 J. F. GRUNDMANN ET AL 2,962,919

GRIPPING DIES FOR PIPE WRENCHES AND SIMILAR DEVICES Filed Feb. 20, 1959 2 Sheets-Sheet 1 962,919 GRIPPING DIES FOR PIPE WRENCHES AND SIMILAR DEVICES Filed Feb. 20, 1959 Dec. 6, 1960 J. F. GRUNDMANN EI'AL 2 Sheets-Sheet 2 WNW gflwxis M nd a Q/ INVENTORS United Stas GRIPPING DIES FOR PIPE WRENCHES AND SIMILAR DEVICES Filed Feb. 20, 1959, Ser. No. 795,313

8 Claims. (Cl. 81-186) This invention relates to dies in gripping tools and, more particularly, is directed to improvements ofthe die element in tools of the type generally known as pipe tongs and to the die element in tools of the type generally known as drill pipe slips, such as are utilized in the oil industry.

This invention is a continuation-in-part of our application Serial No. 761,723 filed September 18, 1958, entitled Pipe Tong Die, now abandoned.

In the prior art, die teeth were formed generally longitudinally and arranged to be on a 90 degree angle to the direction of loading. According to the present invention, it has been found that arranging the die teeth at an acute angle to the direction of loading offers considerable advantages. These advantages are easily understood if the two types of teeth are visualized as being out on a line parallel to the direction of loading and the resulting triangular sections examined and compared. These sections represent the amount of material which resists any given tong load. Thus, the base of the section in the ordinary tooth, which receives the load at 90 degrees to its longitudinal direction, is the shortest base of the tooth; whereas where the cross section is cut at an acute angle, rather than at right angles to the tooth, the section is a broader based triangle which oifers greater strength against shearing or bending than dies of the narrower based, ordinary die tooth.

If the prior art teeth were made of the same section cut at an acute angle-that is, with a broader basethey would be equally strong as the teeth provided in the present invention, but would never have the opportunity to demonstrate this superior strength. The reason for this is that the blunt tooth angle, 90 degrees to the direction of loading, would not allow each tooth to penetrate so that the load could be taken by the thicker portions of the teeth. However, according to the present invention, the load is more concentrated in the lower portion and base of the teeth because they make a quicker, deeper penetration when the pipe is first gripped by the tools. Therefore, the diagonally arranged teeth can carry more load than the longitudinally arranged teeth of the ordinary die.

The diagonally arranged teeth of the present invention not only have a higher penetration angle but, also, strike the pipe or tool joint being gripped for rotation at an angle so that on immediate contact the surface of pipe offers the smallest area to resist the penetrating force. This is in contrast to the teeth aligned to receive the load at a 90 degree angle where the pipe offers the largest area possible to resist the penetrating force.

As the penetration of the tooth continues into the pipe or tool joint surface, the penetration resisting area rapidly becomes larger until it is sufficient to restrain the tent 2,962,919 Patented Dec. 6, 1960 ice 0 in having a double angular contact on the pipe, which clamping force of a tong, for example. This condition 7 occurs at approximately the same tooth penetration depth occurs in using two sets of reversed or crossing diagonal teeth in pipe tongs, for example, all the side thrust is biased out of the die itself so that there is no tendency for the die to move either up or down the pipe regardless of which way the tooth is applied and, therefore, the die functions as well in one direction as another; that is, it is 100 percent reversible.

Still another advantage is that a die made according to the present invention wears much longer than a conventional one. The reason for this is that practically all wear occurs when the die is slipping and, because of the rapid gripping action made possible in the present invention, there is little or no slippage.

A salient feature of the present invention is that a drill pipe slip insert, for example, made according to the present invention, will take two directional loading with the same advantages that a pipe tong die has with one directional loading. That is, drill pipe slip inserts or buttons, made according to the present invention, by having two sets of crossing diagonal teeth, forming a curved gripping configuration complementary to the pipe,- take a rotary horizontal load as well as a vertical supporting load.

A further advantage provided in the present invention is that acute angle contact of the pipe by the die teeth provides an excellent self-cleaning characteristic in the teeth.

It is, therefore, an object of the present invention to provide an improved die having diagonally arranged teeth.

It is another object of the present invention to provide an improved die having inwardly curved, diagonally arranged teeth.

It is a principal object of the present invention to provide a pipe tong die which takes the load on quick, initial penetration so that the load can be taken by a thicker portion of the tooth than is possible with teeth at degrees to the direction of loading.

It is a further object of the present invention to provide a pipe tong die in which the teeth are arranged at an angle so that on contact with a pipe the surface thereof offers the smallest area to resist the penetrating force of the teeth.

It is a still further object of the present invention to provide a pipe tong die in which all the teeth work against the pipe rather than just two rows of the teeth as in the conventional die, where the teeth are arranged to be at a 90 degree angle to the direction of loading.

It is still another object of the present invention to provide a pipe tong die in which the teeth will carry more load than in the conventional die because the load is not concentrated along the tip of the teeth.

It is another principal object of the present invention to provide a drill pipe slip insert or button die having inwardly curved, diagonally crossing lands and grooves in which all the teeth work against the pipe to support it vertically and to grip it against rotary horizontal movement.

Another object of the present invention is to provide dies which are substantially self-cleaning.

It is also a principal object of he invention to provide or dies in which there is little slippage and which, therefore, have an unusually long life.

Other objects of the invention will become apparent from the following description taken in connection with the accompanying drawings, in which: i v i Fig. l is a planv view of a pipe tong having dies em,- bodying the features of the present inventionf Fig. 2 is an enlarged plan view of one of the dies, according to the present invention, looking towards its working face, in the direction of the arrows 2 in Fig. 1;

Fig. 3 is a fragmentary longitudinal sectional view of the die taken substantially on line 3-3 of Fig. 2;

Fig. 4 is a fragmentary sectional view of the die along the line 44 of Fig. 2;

Fig 5 is an enlarged plan view of a die showing another embodiment of the invention;

Fig. 6 is a perspective fragmentary view of a drill pipe slip,'showing inserts having working faces embodying the features of the present invention;

Fig. 7 is a cross-sectional view taken along the line 7,7 of Fig. 6;

Fig. 8 is a perspective view of one of the inserts shown in Fig.6;

Fig. 9 is a view taken along the arrow 9 in Fig. 8;

Fig. 10 is a view taken along the arrow 10 in Fig. 8; and

Fig. 11 is a fragmentary cross-sectional view taken along the direction of the line indicated by arrows 11 in Fig. 8. I

As illustrative of a tool utilizing dies according to the present invention, there is shown in Fig. l a pipe tong die such as used in the oil well industry for screwing together and unscrewing pipe sections.

In generahthe pipe tong comprises a handle, 1, which is tapered from its jaw carrying end to its free end. This handle may be of any suitable construction and for lightne ss may be of I-section to give it greater strength. At its jaw end the handle is provided with a long jaw 2 which is pivoted at one end for swinging movement by means of a pivotal connection including a pintle pin 3. The pivotal connection, which is inwardly spaced somewhat from this end of the handle, may be considered as the working pivot means of the tong.

In operative relation with the long jaw 2, articulate jawrneans are provided consisting of a short jaw 4 pivotally connected at one'end' with an intermediate jaw 5 by a pivotal connection 6. The other end of the short jaw 4 is pivotally connected to the jaw end of the handle 1 by means of a pintle 7 which forms the fulcrum pivot of the tong.

The jaws are arranged to be clampingly secured in operative position around a work piece, in this instance, a pipe 8. For such purpose, the outermost end of the jaw 2 has a latch member 9 mounted for swinging movement about a pivotal connection including pivot pin 10. This latch member is generally U-shaped and includes a fiat latching surface 11 adapted to extend over a flatface or surface 12 of an end lug 13 carried by the intermediate jaw S at its outermost end.

As shown, the jaws 2, 4 and 5 are provided with inner curved faces to generally accommodate them to the pipe surface. In order to grippingly engage the outer surface of the pipe, the jaws are provided with dies 14 which are removably supported as by a dovetail connection.

Referring specifically to Figs. 2, 3 and 4, it will be noted that the die is in general of rectangular construction, and may be fabricated from bar steel having suitable hardness characteristics.

Each die comprises a body portion 15 having a planar back surface 1 6and. side walls 17 which are inwardly inclined toward a forward or working face 18.

As is. clearly shown in Fig. 2, the working face 18 of the die is divided into three portions. The upper portion of the working face in the drawing is formed by the cutting of the diagonal grooves 21 whose outwardly diverging side walls 24 and 25 terminate in diagonal lands or work-engaging edges 19. In other words, the cutting of grooves 21 provides an arrangement of lands forming teeth alternate with the grooves. Here the lands and grooves are shown to be cut at substantially 45 degrees from the longitudinal direction of the die, said 45 degrees having been found in general to be a preferable angle." Similarly, in the lower section of the die are diagonal grooves 22 cut in the reverse direction to grooves 21. In the same manner as above, outwardly diverging:

side walls 26 and 27 of grooves 22 terminate in lands 20.

The central portion of the die is formed by theintersection of a portion of grooves 21 and 22. Here the teeth 23, formed as a result of the intersection of the grooves, are pyramidal. The peaks of the teeth 23 are work-engaging apices. I

To make the die percent reversible-that is, to prevent any side thrust in any positionit is desirable that the cutting face be made symmetrical, as shown in Figs. 2 and 5. This is accomplished by having the lowermost of the upper grooves 21, as in Fig. 2, start at the longitudinal center of the die and, likewise, starting the upper most of the lower grooves 22 at the same point. By so cutting the grooves, the lines of direction of the upper and lower ones will intersect in a transverse line through the center of the working face. In other words, a line. of direction of each groove 21, if extended as may be, necessary, will intersect a corresponding line of direction of groove 22, if extended as may be necessary, in

a transverse straight line either on the working face or.

on an extension of the line beyond the working face.

As shown in Figs. 3 and 4, the grooves 21 and Ham of similar construction and each groove has oppositely inclined rimmed margins which form diverging side walls; 24 and 25, and 26 and 27, respectively. The bottom of the bottom of grooves 21 shows the length of the, baseof the teeth to which the direction of loading is applied in the present invention, the direction being'transverseto the die a-t an acute angle to the teeth. InFig. 4, drawn according to the same scale as Fig. 3, the base ofthe teeth is shown cut along the line 4-4, said cutting line being in the direction of loading against the teeth in a conventional die where the teeth are longitudinal, rather than diagonal, with respect to the elongate die configuration. The longer base, illustrated in Fig. 3, provides greater strength against shearing or bending than does conventional die structure where the load is applied against a shorter base.

In Fig. 5, an embodiment of the invention is shown in which grooves 21a and 22a are not cut beyond the approximate longitudinal center on the die 14a and, as a result, no pyramidal teeth are formed. Thus, in this embodiment, all the work-engaging teeth are in the form of diagonal lands 19a and 20a, extending in reverse directions to each other but at the same numeriealangle with the longitudinal direction of: the diet Here; the die is basically in two sections, one formed by the upper grooves having outw ardly diverging side walls 24:; and 25a, and the other formed by the v lower grooves having outwardly diverging side walls 26a and 2711 Again, if die 14a is made symmetricalfa line "or directionjof each land-and groove in the upper portion, if extended, will intersect 'a corresponding reversed extended line of direction of a land and groove in the lower section at a point on a straight line drawn transversely through the center of the die.

wagers In Fig. 5 it should be noted that where the two oppo- 'sitely directed lands and grooves intersect within the working face of the die, there are formed continuous lands and grooves in the shape of a right angle; that is, if the lands and grooves are formed at 45 degrees with the direction of loading, which is 90 degrees from the longitudinal direction to the die body.

The above-described symmetrical construction permits end-for-end reversal of the die without in any way affecting its operation. The two reversed diagonally directed teeth formed on each set of lands present pressure-applying surfaces and a high penetration tooth angle which strike the pipe or tool at an angle so that on immediate contact the surface of the pipe offers the smallest area to resist the penetrating force.

When made symmetrically, the present invention produces a foolproof construction, and it is unnecessary for an operator in the field to concern himself with the manner in which the die is inserted in the tool since it will function properly irrespective of which end is inserted first. It should be noted that a die, according to the present invention, need not be made symmetrically. Further, the opposing grooves, as 21 and 22 in Fig. 2, can be cut at various intervals over the full working face of the die.

Another illustrative use of the present invention is shown in Figs. 6 and 7 and the embodiment of the invention therein is more specifically shown in Figs. 8-11. Drill pipe slips 30, shown fragmentarily, are used in the handling of drilling tool strings incident to the lowering or raising of such strings into or out of a well casing. The slip is a device which engages the rotary table at' the top of the casing and which, by a wedging or other clamping action, operates to engage and hold the drill string suspended while sections of drill pipe are added or re moved as the drill string is lowered or raised.

One of the most common forms of drill pipe slips is of the general type shown in United States Letters Patent No. 2,119,731. Similar slips are shown in Figs. 6 and 7 and comprise two or more hingedly articulated body members or jaws 31. The outer faces of the body members 31 are shaped to form portions of an inverted frustoconical surface 32a on body frame 32. The axis of the inverted frusto-conical configuration formed by the edging surfaces 32a is substantially coincident with the axis of the drill string and the casing.

Hand-operated slips are raised by means of handles 33, shown in part in Fig. 6. The body members 31 at their inner faces are provided with hardened steel buttons or inserts 35 so as to form a cylindrical configuration adapted to engage a drill pipe and to be pressed into tight engagement therewith by the wedging action effected by the engagement of the outer inclined surfaces 32a of body frames 32 with a bushing (not shown) in the rotary table under the influence of the weight of the tool string which may be several tons. Buttons 35 are inserted in a series of one or more of vertically disposed slots 31a which restrains them against rotation.

The gripping or working face 48 of buttons 35 is formed on one side of body 36 and the integral shank 37 extends centrally and rearwardly therefrom from opposite or back face 49. Buttons 35 may be held in place in the slots by means of a pin 34 in hole 38 in the shank 37 which, in turn, extends outwardly of slots 31a in body members 31 through holes 39.

Buttons 35 have pipe-engaging teeth formed by first and second opposing or crossing diagonal lands 42 and 43, which are formed by the cutting of crossing diagonal grooves 40 and 41, respectively. Grooves 40 are comprised of diverging side walls 44 and 45 which terminate in lands 42, and grooves 41 are comprised of diverging side walls 46 and 47 which terminate in lands 43.

In this embodiment of the invention, the grooves are cut so as to be curved inwardly and so as to form lands which are also curved inwardly to form a curved working face 48. Face 48 is illustrated as being symmetrical,

6 with the deepest point of the curve being at the vertical center of the working face. This presents a fragmentary, cylindrical configuration in cross section, shown in plan in Fig. 9, and which is complementary to the surface of a pipe.

The basic difference between the working face of the embodiment shown in Fig. 8 and those shown in Figs. 2 and 5 is that the lands and grooves in the former are cut to form a fragmentary, but substantially cylindrical, working face 48. Working face 48 provides the gripping means for two directional loading, that is, vertical and horizontal, then being applied due to rotation of the pipe. For either type of loading, the insert 35 may be reversed 180 degrees and perform equally well.

As in the embodiment shown in Fig. 5, whether the direction of loading be a supporting one in the downward vertical direction or whether it be a rotative one at degrees to the center line formed by the points of intersection of the lands 42 and 43, load is applied to a longer and, therefore, more substantial base of the teeth formed by the diagonal lands and grooves as compared with the length of the base of the teeth in an ordinary die in relation to the direction of loading. In Fig. 9, the distance between the bottom of the grooves 40 and 41 shows the length of the base of the teeth to which the direction of loading is applied in the present invention, the direction being transverse to the die at an acute angle of the teeth. The same distance is illustrated in Fig. 10 showing the distance from the base formed from between two nadirs of the grooves 41. In Fig. 11,in the same scale as Figs. 9 and 10, the base of the teeth is shown cut along the line indicated by the arrows 11 of Fig. 8, the plane of the cut or cross-sectional surface being in the direction of loading against the teeth in a conventional die where the teeth are longitudinal rather than diagonal. Here again, the longer base, in Figs. 9 and 10, provides greater strength, both in vertical support and horizontal rotational loading, against shearing or bending than does conventional structure used so that the load is applied against the shorter base.

In Fig. 8, similar to the configuration of Fig. 5, it should be noted that where the two sets: of oppositely directed inwardly curved lands and grooves intersect within the working face of the die, there are formed continuous lands and grooves in the shape of an approximate right angle; that is, the lands and grooves are formed to be at 45 degrees to the directions of loading, either vertical or horizontal.

As in the embodiments shown in Figs. 2 and 5, the embodiment shown in Fig. 8 produces a foolproof construction, and it is unnecessary for an operator in the field to concern himself with the manner in which the die is inserted in the tool since it will function properly irrespective of whether the continuous lands and grooves form inverted Vs as shown in the drawings or upright Vs, not shown. Again, it should be noted that a gripping die, having a working face similar to that of the buttons 35, according to the present invention, need not be made symmetrically.

Thus, while a slip is holding the drill strings suspended incident to the addition or removal of sections of drill pipe, the slip must frequently resist the turning movement of the pipe, and the slip insert, shown in Fig. 8, provides an unusual advantage in that it presents the same holding force in the rotational direction as it does in the vertical supporting direction.

Although the invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only, and is not to be taken by way of limitation, the spirit and scope of this invention being limited only by the terms of the appended claims.

What is claimed is:

1. A pipe tong die comprising: an elongate body structure having a working face; a plurality of first dia onal, parallel, alternate lands and grooves on said working face; :a plurality of second diagonal, parallel, alternate lands and grooves on said working face; said first and second lands and grooves being in crossing directions and being angularly disposed with the longitudinal direction of said elongate die body so that the line of direction of each of said first lands is directed to intersect at line of direction of a corresponding second land at a point intermediate of the length of said die, a plurality of said first and second grooves intersecting intermediately the longitudinal ends of'said die body on said working face to form pyramidal teeth on said working face; said lands having work-engaging edges; and said teeth having work-engaging apices.

2. A pipe tong die comprising: an elongate body structurehaving a working face: a plurality of first diagonal and parallel grooves on said working face; a plurality of second diagonal and parallel grooves on said working face; said first grooves being in opposite direction tosaid second grooves; said first and second grooves being angularly disposed with respect to the longitudinal direction of said elongate die body; said first grooves having outwardly diverging side walls cooperating to form a first diagonal row of elongate teeth at one end of said body; said second grooves having outwardly diverging side walls cooperating to form a second diagonal row of elongate teeth at the other end of said body; said teeth having work-engaging edges; a portion of said first and second grooves intersecting each other on said Working face at a central portion intermediate the ends of said die body and forming pyramidal teeth in said central portion; said teeth having substantially pointed work-engaging apicest 3. A gripping die comprising: an elongate body structure having a working face; a plurality of first diagonal, parallel, alternate lands and grooves on said working face; aplurality of second diagonal, parallel, alternate lands and grooves on said working face; said first and second lands and grooves being in crossing directions and being angularly disposed with the longitudinal direction of said elongate die body so that the line of direction of each of said first lands is directed to intersect a line of direction of a corresponding second land at a point intermediate of the length of said die, a plurality of said first and second grooves intersecting intermediately the longitudinal ends of said die body on said working face to form teeth on said working face; said lands having work-engaging edges; and said teeth having work-engaging apices.

4. The invention as defined in claim 3, wherein the lines of directions of all of said lands are straight lines.

5. A gripping die comprising: a unitary elongate body structure made of a single piece of metal having a working face; a plurality of first diagonal, parallel, alternate lands and grooves on said working face; a plurality of second diagonal, parallel, alternate lands and grooves on said working face; said first and second lands and grooves being in crossing directions and being angularly disposed with the longitudinal direction of said elongate die body so that the line of direction of each of said first lands is directed to intersect a line of direction of a corresponding second land at a point intermediate of the length of said die, said lands having work-engaging edges.

6. A pipe gripping tool comprising: a tool body adapted to hold a gripping die against a pipe, said tool body being adapted to hold said pipe with its axis extending in a predetermined direction therethrough; a gripping die including an elongate body structure having a working face, said gripping die being mounted in a position in said tool body such that the longitudinal axis of said elongate die body lies parallel to said pipe axis; a plurality of first diagonal, parallel, alternate lands and grooves on said working face; a plurality of second diagonal, parallel, alternate lands and grooves on said working face; said first and second lands and grooves being in crossing directions and being angularly disposed with the longitudinal direction of said elongate die body so that the line of direction of each of said first lands is directed to intersect a line of direction of a corresponding second land at a point intermediate of the length of said die, said lands having work-engaging edges.

7. A pipe gripping tool comprising: a tool body adapted to hold a gripping die against apipe, said tool body being adapted to hold said pipe with its axis extending in a predetermined direction therethrough; a gripping die including a unitary elongate body structure made of a single piece of metal having a working face, said gripping die being mounted in a position in said tool body such that the longitudinal axis of said elongate die body lies parallel to said pipe axis; a plurality of first diagonal, parallel, alternate lands and grooves on said working face; a plurality of second diagonal parallel, alternate lands and grooves on said working face; said first and second lands and grooves being in crossing directions and being angularly disposed with the longitudinal direction of said elongate die body so that the line of direction of each of said firstlands is directed to intersect a line of direction of acorresponding second land at a pointintermediate' of the length of said die, the lines of directions of all of said lands being straight lines, said lands having work-engaging edges.

8. A gripping die comprising: an elongate body structure having a working face; a plurality of first diagonal, parallel, alternate lands and grooves on said working face; a plurality of second diagonal, parallel, alternate lands and grooves on said working face; said first and second lands and grooves being in crossing directions and being angularly disposed with the longitudinal direction of said elongate die body so that the line of direction of each of said first lands is directed to intersect a line of direction of a corresponding second land at a References Cited in the file of this patent UNITED STATES PATENTS 1,908,421 Heggem May 9, 1933 2,098,369 Baash Nov. 9, 1937 2,294,548 Gordon Sept. 1, 1942 2,326,962 Meier Aug. 17, 1943 2,720,128 Woolley Oct. 11, 1955 2,760,395 St. Pierre Aug. 28, 1956 2,873,636 Sherman Feb. 17, 1959 

